A drone view purportedly shows the destruction of a Russian long-range anti-aircraft system near Olenivka, Crimea, in this screen grab taken from a handout video released 23 August 2023. Ukrainian Main Directorate Of Intelligence/Handout via Reuters

The use of drones in warfare is becoming ever more prevalent. Global Insight assesses the many legal issues this has created.

Drones are playing an increasingly prominent role in the war in Ukraine. In the Red Sea, Houthi rebels have used these unmanned aerial vehicles – which are difficult to defend against and cheap to buy – to disrupt shipping. In the Israel-Hamas conflict, both sides have deployed them against targets, and Iran has attacked Israel with massive drone strikes of its own.

While the use of drones to attempt precision strikes on key military or terrorist personnel is nothing new, the scale and use to which they are put has evolved rapidly during the conflict in Ukraine. After a visit to Kyiv in 2024, for example, ex-Google Chief Executive Officer Eric Schmidt said that ‘the future of war will be dictated and waged by drones’. Schmidt’s startup, White Stork, is reportedly developing AI-powered attack drones.

While Russia has conventional air superiority, it has used its aircraft sparingly after early attempts to dominate the skies were thwarted by Western-produced anti-aircraft systems. As an alternative, both sides in the conflict have turned increasingly to drones. Initially, that included large, fixed-wing, long-range weapons that could carry heavy payloads, such as Ukraine’s Turkish Bayraktar TB2 and the more recent AQ400 Scythe drones. Russia’s Iranian-built Shahed drones have been modified and improved to avoid radar detection and carry heavier loads. Russia has relentlessly targeted Ukraine’s cities and energy infrastructure since 2022 and, more recently, Ukraine has used its long-range drones to attack Moscow and key resources.

But perhaps the most significant development has been the scale at which so-called first-person-viewpoint (FPV) drones – which can be bought over-the-counter and modified – are now used. These are compact, cheap devices that carry small amounts of explosives and are used for reconnaissance, targeting vehicles and troops, and for propaganda. Anyone who can play video games would be at home using such devices. Controllers can simply hide in a bunker and hunt down targets.

Such smaller weapons are making a decisive difference on the battlefield. Ukraine’s incursion into the Russian region of Kursk in the summer, for instance, relied heavily on drones to both scan the landscape and clear defensive positions. Similarly, Russia’s advances in the east of Ukraine follow the same pattern – a wave of drones, followed by artillery bombardment, missile attacks and ground forces. While they are cheap – costing less than $1,000 each – drones pack a punch big enough to destroy US-made Abrams tanks, which individually cost upwards of $10m.

The evolution of legal opinion

All this brings the legal position on drones into sharp focus. In 2013, Christof Heyns – the then UN Special Rapporteur on extrajudicial, summary or arbitrary executions – presented a paper to the UN General Assembly, which was later published as a multi-author document outlining the international framework regulating the use of armed drones. In brief, it argued that for drone strikes to be legitimate they needed to satisfy the legal requirements in three broad areas: those regulating the use of force, humanitarian law and international human rights.

At the 27th session of the UN Human Rights Council in 2014, the International Committee of the Red Cross (ICRC) agreed that while the weapons were new, ‘there are also no inherent features of drones that would prevent their operators from observing the relevant rules of this body of law’. Much of the debate at that time related to the use of drones to target terrorist leaders – recent conflicts in both Israel-Gaza and Ukraine-Russia have, however, placed greater emphasis on the use of such weapons in open combat.

Given the pre-programming and live targeting capabilities inherent in such technologies, who and what is hit should be much more accurate when compared with many conventional weapons. But mass attacks by long-range drones often miss their targets and kill civilians – and it’s impossible to know under the fog of war whether military personnel are using civilian buildings to hide their presence.

From a legal perspective, under international human rights law, ‘it is a “cardinal principle” that states must at all times distinguish between combatants and civilians when targeting individuals, and between civilian objects and military objectives’, according to a 2017 background paper by the IBA’s Human Rights Institute; indiscriminately firing weapons into areas without consideration of potential causalities among non-combatants is clearly unlawful by this definition.

The issue is clearly complex. Where both sides are targeting energy infrastructure, the question arises as to whether those are civilian or military targets. While the Geneva Convention forbids attacks on ‘civilian objects’, energy serves the needs of an entire nation. Military law expert Michael Schmitt has said that power infrastructure is a legitimate target if armed forces receive a definite military benefit – such as the ability to refuel tanks – that would be prevented by an attack.

Proportionality is also important. It’s necessary to calculate which party – military or civilian – suffers the most. If the impact on civilians is excessive, then such strikes fail the test. ‘The incidental loss of life and injury to civilians that can be expected seems very large given that power outages are making it impossible for surgeons to carry on their work, affecting people’s access to healthcare, and creating conditions in which vulnerable people are dying due to the cold or hunger’, said Katharine Fortin, a senior lecturer of public international law and human rights at Utrecht University’s Netherlands Institute of Human Rights, when interviewed about Russia’s continual strikes on Ukraine’s energy infrastructure.

Personalised strikes

As both sides advertise their successful drone strikes on the internet via military bloggers, one can say that the accuracy of FPV drones compared with many other weapons is impressive. They can fly through open windows, hit communication posts, be driven into the vulnerable parts of armoured vehicles and kill individual infantry as they cross through a city or field. Commanders also use them for surveillance and to check the success of military actions. Their constant whining is a psychological drain on troops across the battle zone.

While this detailed accuracy seems to hugely reduce risk to civilians, at least in one respect, legal problems persist. In combat against insurgent groups – often people who look and dress like civilians – commentators have pointed to the prevalence of cognitive bias among controllers that has led to the death of non-combatants. While military leaders are well-aware of these problems, ‘aerial visuals do not eliminate the problem of bias and distortion, but rather shift the location and association of the bias into the space of image interpretation’, according to an award-winning paper by Shiri Krebs, a professor of law at Deakin University in Australia and the Director of the Centre for Law as Protection.

Even if there is correct identification and targeting of military equipment and personnel, FPV drones may still infringe international legal frameworks. First, the targeted killing of individuals by any unmanned weapon raises the issue of extrajudicial executions, which violate the fundamental rights adopted by the UN. ‘Here, it is undoubtedly crucial that there exists, in conjunction with the principle of necessity, a requirement for an obvious and imminent threat’, according to an article in the Rule of Law Journal.

More controversially, debates in international humanitarian law have focused on ICRC guidance that attempts to balance the use of lethal force with a combatant’s right to surrender. ‘It would defy basic notions of humanity to kill an adversary or to refrain from giving him or her an opportunity to surrender where there manifestly is no necessity for the use of lethal force’, the guidance said. But critics argue that states have already decided that it’s necessary and proportionate to target combatants during war. And while videos showing soldiers surrendering to drones occasionally appear, the machines mostly strike to kill.

The framework governing the use of force, humanitarian law and international human rights certainly covers the use of drones. But the consistent enforcement of these rules currently appears to be lagging far behind the increasingly widespread – and, in some cases, quite devastating – use of the this increasingly sophisticated technology.

Arthur Piper is a freelance journalist. He can be contacted at arthur@sdw.co.uk